DESCRIPTION (adapted from the principal investigator's abstract) The treatment of BPH has been redefined over the past decade. Medical therapy is currently widely accepted for the treatment of BPH. Medical therapy has a unique appeal for the treatment of clinical BPH since the side effects of medical therapy are minor and reversible, and therapy is simply terminated if the adverse experiences are severe or the treatment ineffective. Approximately 10 million American males over the age of 50 years have moderate/severe urinary symptoms secondary to BPH. The estimated annual cost of medical therapy for all American males affected with clinical BPH is 3.6 billion dollars. Since health care resources are limited, it is imperative that the value of medical therapy be defined. Ascertaining the value of any BPH treatment requires an understanding of the natural history of the disease, the initial and long-term effectiveness and morbidity of therapy, and the impact of therapy on disease progression. The NIH has committed significant resources to conduct a full scale clinical trial with the primary objective to determine if medical therapy delays or prevents the progression of BPH. The study design will also allow for a direct comparison of the immediate and long-term safety and efficacy of alpha blockade (Doxazosin) and hormonal therapy (Finasteride) for BPH. Approximately 2,800 will be enrolled at 14 Clinical Centers throughout the United States over a two-year period. The inclusion and exclusion criteria are intended to identify men with significant clinical BPH without absolute indications for surgical intervention. The Department of Urology at New York University (NYU) Medical Center has the personnel, facilities, patient referral base, institutional support, and commitment to serve as an effective Clinical Center for the NIH sponsored full scale clinical trial on BPH. The investigators indicate that the present grant application will demonstrate that both the principal and co-principal investigators have participated in numerous randomized clinical trials, evaluating the safety and efficacy of both medical and device therapy for BPH. The NYU Medical Center, Department of Urology served as one of the six clinical centers for the initial BPH-pilot study. The performance of this center, during the pilot study, indicates the competence and commitment of the support staff and the ability of the clinical center to enroll sufficient patients into a randomized placebo-controlled clinical trial. The ethnic distribution of patients enrolled into the pilot study at the NYU Clinical Center demonstrates that the center will be in compliance with the NIH Revitalization Act of 1993. The investigators hope that the proposed clinical center will have the opportunity to participate in this landmark BPH clinical trial.